1. Field of the Invention
The present invention relates to a film image conversion apparatus for reading an image on a film using a linear image sensor, and converting the image into an electrical signal, and a photo-telegraphy apparatus for transmitting the electrical signal.
2. Related Background Art
FIG. 2 shows a conventional film image conversion apparatus.
In FIG. 2, a projection optical system 3 and a linear image sensor 4 are mounted on an optical base 12 to constitute a projection optical system block.
A scanning stage 2, a film holder 5, a stepping motor 8, a joint 9, a lead screw 11, and stage guide bars 10 are mounted on a scanning mechanism base 13 to constitute a scanning mechanism block.
Since the scanning mechanism system block and the projection optical system block respectively have independent base units, i.e., the optical base 12 and the scanning mechanism base 13, they are fastened by a fixing screw 14.
When an image on a film is converted into an electrical signal, a light beam emitted from a light source 7 is transmitted through a film original 6 held on the film holder 5 arranged on the scanning stage 2. The transmission light beam is focused on the linear image sensor 4 by the projection optical system 3. The linear image sensor 4 converts the focused light beam into an electrical signal according to an image of the film original 6 (main scanning).
At the same time, the lead screw 11 is driven through the joint 9 by the stepping motor 8 controlled by a control system (not shown), and the scanning stage 2 is moved in the subscanning direction.
As a result, the entire image of the film original 6 is converted into an electrical signal by the linear image sensor 4.
The stage 2 is driven by the lead screw 11, and is moved along the two stage guide bars (linear guide mechanism) 10. Thus, movement of the stage 2 in directions other than the longitudinal direction caused by poor working precision of the lead screw 11 is suppressed.
The conventional film image conversion apparatus described above suffers from the following problems.
(1) Since the step of assembling the base units of the scanning mechanism system block and the projection optical system block by the fixing screw is required, the number of assembling steps of the film image conversion apparatus is undesirably increased.
(2) When the block units of the two blocks are fixed, the assembling precision must be improved, and the precision of each of components constituting the two blocks must be improved.
(3) In order to provide a sufficient mechanical strength to the coupling portion between the base units of the two blocks, the thicknesses of the base units corresponding to the coupling portion must be increased. For this reason, the base units become bulky, and the weight of the film image conversion apparatus itself is undesirably increased.
(4) Since no component is interposed between the scanning mechanism system block and the projection optical system block, a lubricant applied to a driving portion such as the lead screw mounted on the scanning mechanism base is scattered toward the projection optical system, and contaminates lenses of the projection optical system.
A conventional photo-telegraphy apparatus has an arrangement as shown in FIGS. 12 and 13. FIGS. 12 and 13 are respectively a plan view and a side view showing a structure of the conventional photo-telegraphy apparatus.
In FIGS. 12 and 13, a 35-mm film as an original is mounted on a film holder 107. The apparatus main body has a notched portion 130 as a space for an operation for mounting the film holder 107. A horizontally movable stage 106 is arranged on the vertical surface of the notched portion 130, and the film holder 107 is detachably attached on the stage 106. When the length of the film original is larger than the width of the notched portion 130, the film original 130 must be cut into a proper length or must be wound.
After the film holder 107 is attached to the stage 106, a light-shielding lid 134 for closing the notched portion 130 is closed so as to shield external light.
The film holder 107 has a window corresponding to one frame of the film, and this window portion is subjected to transmission illumination.
An illumination optical system for performing transmission illumination of the film includes a lamp 112, a 45.degree. mirror 113, and a condenser lens 133.
Light emitted from the lamp 112 is reflected by the 45.degree. mirror 113, and is radiated on the film original in the film holder 107 via the condenser lens 133. The light transmitted through the film original passes through a zoom lens 114, and is then guided to a finder 132 via a 45.degree. mirror 131.
A user can see an optical image displayed on the finder 132 when he or she operates the zoom lens 114 to perform a trimming operation.
When the film image is read, the 45.degree. mirror 131 is pivoted upward. In this case, transmission light of the film via the zoom lens 114 is focused on a CCD line sensor 115.
When the stage 106 on which the film holder 107 is attached is horizontally moved, an image is sequentially focused on the CCD line sensor 115 in units of lines, thereby reading the entire image.
The image focused on the CCD line sensor 115 is converted into an electrical image signal. The electrical image signal is subjected to various signal processing operations, and the processed signal is then output outside the apparatus.
The read image is displayed on a display screen 139a of a monitor device 139.
An operation unit 135 is connected to the photo-telegraphy apparatus main body via a cable 136. An operation such as menu selection can be performed by depressing an operation button while observing an LCD (liquid crystal display).
In the above-mentioned photo-telegraphy apparatus, an optical system including the 45.degree. mirror 113, the condenser lens 133, the zoom lens 114, the 45.degree. mirror 131, and the like; a mechanism section consisting of the stage 106, and its driving unit; and electrical circuit units 137 and 138 for processing an image signal, and for controlling the mechanism section, the operation unit 135, and the like are arranged together.
In the conventional structure, the optical system, the mechanism section, and the electrical circuit sections are arranged together. Since the film holder is mounted in the notched portion in the upper portion of the apparatus, the optical system is arranged in the upper portion of the apparatus. For this reason, the electrical circuit unit 137 and a power supply 121 are arranged in a lower portion of the apparatus.
With this arrangement, in particular, the electrical circuit unit 137 and the power supply 121 are arranged in the lower portion of the apparatus, and this results in poor workability in maintenance.